In the midst of Celtic’s desperate struggles against Cluj, there seemed simple dots to join. And no wonder. Their balance looked entirely upset by fielding Callum McGregor as a makeshift left-back in their failed chase for a £25 million Champions League bounty… a mere five days after they cashed a £25m million chip in the shape of their prized left-back Kieran Tierney.

There were only a few issues with this simplistic reading of what left Celtic with a left-back-shaped hole down which McGregor seemed to disappear in the first period – before the entire team kept digging themselves out and into ditches during a bonkers second half that will spark bitter recriminations.

Benched: Boli Bolingoli

The simple truth is that, had Tierney not sought to better himself at Arsenal he would have been no more than a spectator at the third qualifying round encounter, as the 22-year-old is still a month away from playing following pelvic problems that required him to have a double-hernia operation in May.

The fact that there was never any prospect of Tierney playing in these Champions League qualifiers, then, places question marks over Celtic’s recruitment, yet not in the manner that might have been imagined.

McGregor was pressed into action in a role he toiled in for a torturous 45 minutes because Neil Lennon patently didn’t trust the man signed precisely for assignments such as this – the £3 million acquisition Boli Bolingoli.

It isn’t difficult to see why the Celtic manager arrived at this conclusion. It would be generous to suggest that the 24-year-old Belgian has had an erratic opening month to his Celtic career.

Lennon said he opted for McGregor in a berth the player had last occupied in feverishly debated circumstances as Celtic were well beaten by Rangers at Ibrox at the turn of the year because he wanted to incorporate Olivier Ntcham.

The reality is, though, that the personnel switch – on an evening when Lennon said he required his technicians – was down to Bolingoli struggling to avoid giving the impression he can’t get to grips with the requirements of his new club following the move from Rapid Vienna.

Mistakes, misplaced passes and positional misjudgements have all dogged him across his early appearances – not least in the continental domain. In Bolingoli’s defence they were ten-a-penny when he was nowhere to be seen last night. And therefore nowhere to be scapegoated.

Moreover, Bolingoli is not the first Celtic player to be signed for Champions League qualifiers only to then not be trusted in them. It is why, whatever will now be said, the left-back issue should have been addressed in the January transfer window, and a player then bedded in – Tierney hardly featuring throughout the second half of a campaign that had all the signs of possibly being his last.

Celtic’s escape in a Champions League qualifier against Shakhter Karagandy in 2013 offers a case in point. There was a player that suffered Bolingoli’s fate this past week, who was selected for an away leg lost 2-0 but after looking anything but the part in the defeat was dropped – in favour of Efe Ambrose – for a return that Celtic squeaked through with an injury-time clincher to completely overturn the two-goal deficit.

That player, who is on the threshold of winning the Ballon D’Or after becoming a Champions League winner, just happens to be Virgil van Dijk. The seeds of Celtic’s downfall last night have long been in the sowing.